I know it's in Runner's World so maybe something is lost in translation, but these key workouts sound like virtually all of them are training for a half-marathon, not an actual marathon.
Majority are doing 8-10 miles total around marathon pace or slightly faster and breaking that up into 2-3 intervals and adding in another 5-12 of much easier running. A few are doing 15-16 mile tempos. Ritz did about 15 at marathon pace. Neely Spence didn't give specifics.
For the most part is this how American's prepare for the marathon?